Rgg proteins associated with internalized small hydrophobic peptides: a new quorum-sensing mechanism in streptococci
Article first published online: 30 MAR 2011
© 2011 Blackwell Publishing Ltd
Volume 80, Issue 4, pages 1102–1119, May 2011
How to Cite
Fleuchot, B., Gitton, C., Guillot, A., Vidic, J., Nicolas, P., Besset, C., Fontaine, L., Hols, P., Leblond-Bourget, N., Monnet, V. and Gardan, R. (2011), Rgg proteins associated with internalized small hydrophobic peptides: a new quorum-sensing mechanism in streptococci. Molecular Microbiology, 80: 1102–1119. doi: 10.1111/j.1365-2958.2011.07633.x
- Issue published online: 9 MAY 2011
- Article first published online: 30 MAR 2011
- Accepted manuscript online: 25 MAR 2011 03:30AM EST
- Accepted 10 March, 2011.
We identified a genetic context encoding a transcriptional regulator of the Rgg family and a small hydrophobic peptide (SHP) in nearly all streptococci and suggested that it may be involved in a new quorum-sensing mechanism, with SHP playing the role of a pheromone. Here, we provide further support for this hypothesis by constructing a phylogenetic tree of the Rgg and Rgg-like proteins from Gram-positive bacteria and by studying the shp/rgg1358 locus of Streptococcus thermophilus LMD-9. We identified the shp1358 gene as a target of Rgg1358, and used it to confirm the existence of the steps of a quorum-sensing mechanism including secretion, maturation and reimportation of the pheromone into the cell. We used surface plasmon resonance to demonstrate interaction between the pheromone and the regulatory protein and performed electrophoretic mobility shift assays to assess binding of the transcriptional regulator to the promoter regions of its target genes. The active form of the pheromone was identified by mass spectrometry. Our findings demonstrate that the shp/rgg1358 locus encodes two components of a novel quorum-sensing mechanism involving a transcriptional regulator of the Rgg family and a SHP pheromone that is detected and reimported into the cell by the Ami oligopeptide transporter.